Snap spring operated switch



Dec. 26, 1950 J; F. OBRIEN ETAL SNAP SPRING OPERATED SWITCH Original Filed 001;. 30, 1945 2 Sheets-Sheet 1 INVENTORS EPH OBRIEN Dec. 26, 1950 J. F. OBRIEN EI'AL 2,535,090

SNAP SPRING OPERATED SWITCH Original Filed Oct. 30, 1943 2 Sheets-Sheet 2 INVENTOR E OBRIEN RL S 5 a 773W Patented Dec. 26, 1950 @TENT OFFiCE SNAP SPRHNG OPERATED SWITCH Joseph GBrien, Lebanon, and Earl S. Boynton, East Grange, N. .l., assignors to John B. Pierce Foundation, New York, N. FL, a corporation of New York 6 Claims.

invention relates to electromagnetic electromagnetic switch, the relative position of the snap spring and the solenoid operator being disposed within the casing in a pie-established dimensional arrangement to insure accuracy of operation.

It is an object of the invention to provide improved means for confining within the housing of an electromagnetic switch, the operating elements thereof.

It is an object of the invention to provide an electromagnetic switch with improved contact structures.

It is an object of the invention to provide an electromagnetic switch having a fixed and a movable contact organization, with improved means for cushioning the engagement between the fixed and movable contact.

It is an object of the invention to provide an electromagnetic switch comprising a plurality of operating parts, with improved means for securing said operating parts within a housing, wit, a minimum of fastening or attachment means for said operating parts.

It is an object of the invention to provide an electromagnetic switch which is of simple, low cost construction, and which may be assembled, with accurately disposed securement of the operating parts, by means of unskilled labor.

According to a preferred form of the invention, the improved electromagnetic switch comprises an organization of fixed and movable contacts, the movable contacts being brought into or out of engagement with the fixed contacts by solenoid actuators, operating through the agency of a spring. Secured to the base of the housing of the electromagnetic switch, on which base the fixed contacts are positioned, are a plurality of side frame members, said members having at a pre-determined location with respect to the base structure, means to receive and position a sub-base which serves as the support for the operating elements of the electromagnetic switch. Positioned u on said sub-base, but not permanently afiixed thereto, are a snap spring retainer and a soleno d actuator comprising a of individual solenoid cups between which, and in engagement with the rims thereof are located a pair of spacer members having inner peripheral flanges which collectively provide a cylindrical chamber within which a solenoid core is slidably positioned. The respective solenoid once, within which the operating solenoids are contained, are in stacked relationshi one with the other, and may be inserted within the side frame members by being successively placed therein by the workman. Near the outer end of each of said side frame members is an aperture ada ted to receive the tongue of a rigid bridge which overlie the outermost solenoid cup in spaced relationship therewith. Said bridge member has any desired plurality of tapped openings which receive set screws or the like, the ends of which bear against the top wall of the outermost solenoid cup. U on tightening the set screws the respective operating elements are urged one against the other, and in tight relationship with the sub-base which forms the sup ort for the collective operating members.

The bridge member also aiTords means of securing an outer casing and a too closure plate to complete the housing of the device.

The movable contacts are carried by a flexible plate operatively associated with the magnetic armature whereby the movable contacts are resi iently supported in a manner afiording selfadjustability with respect to the fixed contacts. The flexible disc carrying the movable contacts gives under the impact of the movable contacts against the fixed contacts thereby cushioning the same and dampening chatter during the making of the contacts, resulting in improved circuit closing characteristics and enhancing the life of the respective contacts.

A feature of our invention is an improved assembly structure for an electromagnetic switch.

A feature of our invention is an improved contact organization for an electromagnetic switch.

Other features and advantages will hereinafter appear.

In. the drawings:

Fig. l is a sectional 'view of a preferred form of netic switchembodying the present invention Fig. 2 is a central sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 1.;

Fig. 4 is a sectional view taken on line 44 of Fig. 1.;

Fig. 5 is another sectional elevation of the device, in closed circuit position, the line of section being on the line 5-5 of Fig. 1;

Fig. 6 is an exploded perspective view of the structure; and

Fig. 7 is a side elevation, partly broken away, of the assembled structure, with the outer casing broken away to illustrate the positioning of the parts; Fig. 7 shows a typical wiring diagram.

Referring to the drawings, the housing of our improved electromagnetic switch l8 includes a base plate ii, shell 52 and cap [4; these parts are of insulating material. Secured to the base plate i I, as by any desired plurality of screws or rivets, is an open frame comprising side pieces i5, 5 5 within which the operating elements of the electromagnetic switch are contained and secured. As shown in Figs. 1 and 6, each frame member, at a location suitably above the base has a pair of ears H, H struck inwardly in a common plane; upon said ears rests a plate 18 which serves as a base for the solenoid and snap spring mounting structure, as later described. Legs IS of said base E8 extend downwardly between and in engagement with the side edges of the spaced ears [1, I! of the respective side frame members, and plate IB is thereby held against rotation without the necessity of welding or like means.

At the center of plate I8 is a square opening, bounded on two opposite sides by downwardly extending guide walls 2%}, 29.

Two arcuate side walls 2|, 2!, diametrically placed, extend upwardly from plate !8 to receive and position snap-spring retaining rings 22, 23 and the cup 25 of a solenoid 26, said elements merely being set into position on said base plate i8, without securement thereto. As shown in Fig. 5, ring 22 is shouldered for cooperation with the ring 23 to provide a circular groove within which is confined the rim portion of a snap spring 24.

A second solenoid cup 2'! houses a solenoid 28; between the solenoid cups 25 and 2'! are a pair of flanged spacer members 29, 35, the outer flanges 31, 32 of which fit snugly between and in contact with the frame side-pieces l5, l6, and the inner cylindrical flanges 33, 34 provide a guide sleeve for a magnetic armature 35, axially slidable therein.

To each of the solenoid cups 25, 27 is attached a pole-piece 35, 3?, the axial passage of the latter being concentric with respect to the cylindrical flanges 33, 34, to permit the guided slidable passage of the actuator rod 38, secured to armature 35.

The respective solenoid cups 25 and 21, ring members 29, 39, and pole-pieces 35, 31 are preferably of steel or other magnetic material.

The entire assembly previously described is maintained in proper operative position without individually securing each of the respective elements by means of a bridge M! which extends between the side frame pieces 15, 15,120 pass through a hole adjacent the ends thereof, see Figs. 4 and 5. One or more set screws 45, 45, pass through the bridge 45 to bear against solenoid cup 21, in this manner adjustably holding the respective solenoid cups, cup spacers .and snap spring rin members in position against the base plate 18. Walls 2!, 2: of plate !8 prevent the rings 22, 23, and solenoid cup from shifting laterally, and the side frame members I5, I 5, against which the flanges 3|, 32 of solenoid cup spacer rings 28, 39 abut, insure that the solenoid cup 27 is held against movement.

The bridge also serves to hold the cap l4 and casing 2 in position, by the screw 42.

Snap spring 24 has an opening through its center to receive the reduced diameter, threaded, end of the actuator rod 38, which is secured to a rectangular block 123 of insulation material, the latter passing through the square central opening in plate 53. The Walls 26, 20 act as bearing guides for the block 43.

Secured to the other end of the block 43 by means to prevent relative rotation is a preferably flat spring 44 which carries, by means of rivets 35, (=5, see Fig. 1, a contact bridge 55 preferably metallic having at diametrically spaced locations contacts :37, 47, said contacts cooperating with contacts 43 fixed to the insulating base. Furthermore, the block 43 and the threaded eleinents extended coaxially therein, constitute a rigid member centrally connecting the snap spring and the fiat spring. See Figs. 1 and 5. Suitaole terminal pieces 45) are provided for connection contacts 48, 48 into the circuit to be controlled.

As Fig. 3 shows, the rivets 45 are at a spacing of with respect to the contacts 4?, 41. Such arrangement affords a substantial measure of self-adjustability of contacts 41 with respect to contacts 138, 58, while providing an otherwise rigid supporting structure for said contacts 47.

Referring to Fig. 7, the respective solenoids 26 and 28 are connected into a common circuit for remote control by a momentary-contact switch S, through the illustrated terminals on cap 24. The contacts 41, 18 are in the circuit to be controlled. The solenoid coils may or may not be wound for low voltage actuation, according to preference.

The actuation of solenoid 26 drives the armature to the right as shown in Fig. 5, thereby causing the snap spring 24 to throw into its second position of stable equilibrium as is shown in said figure and bringing the contacts 4'! into engagement with the terminal contacts As will be observed, the block 133 forms a member centrally connecting the snap spring 25 and the flat spring 45. The spring 44 flexes under the impact of the contacts, acting to dampen the engagement of the said contacts and preventing rebound. Desirably, the engagement of the respective contacts is prior to the attainment of full throw position of the snap spring, whereupon said snap spring acts continually to exert a yielding pressure against the spring 3 and in turn against the fixed contacts.

On reverse movement of the armature under the attraction of solenoid 28 the spring 24 snaps to its reverse position of equilibrium to open the contacts 41, 48. The reaction of spring 54 assists in the breaking of the contacts at high speeds.

Whereas we have described our invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made provided they do not depart from the scope of the claims.

We claim:

1. For bridging the fixed contacts of an open electrical circuit, movable contacts disposed adjacent the fixed contacts for movement thereagainst, a metallic contact bridge carrying said movable contacts, and means for moving said movable contacts into engagement with the fixed contacts of the circuit, said means comprising a rim-confined snap spring, a fiat spring spaced apart from and fixed to said contact bridge at points thereon spaced an-gularly from said movable contacts, and a rigid member centrally connecting said snap spring centrally with said fiat spring, whereby said movable contacts will have u a substantial measure of self-adjustability in their engagement with the fixed contacts, and whereby engagement of said movable contacts with said fixed contacts will be dampened by the resiliency of said fiat spring.

2. For bridging the fixed contacts of an open electrical circuit, movable contacts disposed adjacent the fixed contacts for movement thereagainst, a metallic contact bridge carrying said movable contacts diametrically spaced thereon, and means for moving said movable contacts into engagement with the fixed contacts of the circuit, said means comprising a rim-confined snap spring, a fiat spring spaced apart from and fixed to said contact bridge at points thereon spaced substantially ninety degrees from said movable contacts, and a rigid member centrally connecting said snap spring centrally with said fiat spring, whereby said movable contacts will have a substantial measure of self-adjustability in their engagement with the fixed contacts, and whereby engagement of said movable contacts with said fixed contacts will be dampened by the resiliency of said fiat spring.

3. For bridging the fixed contacts of an open electrical circuit, movable contacts disposed adjacent the fixed contacts for movement thereagainst, a metallic contact bridge carrying said movable contacts diametrically spaced thereon, and means for moving said movable contacts into engagement with the fixed contacts of the circuit, said means comprising a rim-confined snap spring, a fiat spring spaced apart from and fixed to said contact bridge at points thereon spaced angularly from said movable contacts, a rigid member centrally connecting said snap spring centrally with said flat spring, and a guide for maintaining said movable contacts in an axial alignment with th fixed contacts of the electrical circuit, whereby said movable contacts will have a substantial measure of self-adjustability in their engagement with the fixed contacts, and whereby engagement of said movabl contacts with said fixed contacts will be dampened by the resiliency of said fiat spring.

4. A bridging contact member for making and breaking an electrical circuit through open fixed contacts thereof, said member comprising movable contacts adjacent the fixed circuit contacts, a metallic bridge carrying said movable contacts, and means supporting said bridge for movement toward and away from the fixed circuit contacts, said means comprising a flat spring spaced apart from and fixed to said bridge at points spaced substantially ninety degrees from said movable contacts, and a rim-confined snap spring spaced from and rigidly connected to said flat spring centrally of said snap spring and said flat spring, whereby said movable contacts may be snapped into self-adjustable, dampened resilient engagement with the fixed circuit contacts.

5. A bridging contact member for making and breaking an electrical circuit through open fixed contacts thereof, said member comprising movable contacts adjacent the fixed circuit contacts, a metallic bridge carrying said movable contacts, and means sup-porting said bridge for movement toward away from the fixed circuit contacts, said means comprising a fiat spring spaced apart from and fixed to said bridge at points spaced substantially ninet degrees from said movable contacts, a rim-confined snap spring spaced from and rigidly connected to said fiat spring centrally of said snap spring and said fiat spring, and a guide for maintaining said movable contacts in axial alignment with the fixed contacts of the electrical circuit, whereby said movable contacts may be snapped into self-adjustable, dampened resilient engagement with the fixed circuit contacts.

6. In an electromagnetic switch wherein solenoid-induced movement of a two-position spring member act-dates a bridge of conductive material having two spaced electrical contacts thereon to move such spaced contacts against fixed contacts to close a circuit and to separate such spaced contacts from such fixed contacts to break th circuit, the combination with the two-position spring member and the bridge of a fiat spring centrally connected to said two-position spring and spaced apart from and fixed to said bridge at points thereon spaced angularly from the contacts carried thereby.

JOSEPH F. OBRIEN. EARL S. BOYNTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 363.250 McElroy May 17, 1887 803,486 Hill Oct. 31, 1905 883,059 Starrett Mar. 24, 1908 1,238,667 Halbleib et a1 Aug. 28, 1917 1,319,880 Little Oct. 28, 1919 1 817,155 Leece Aug. 4, 1931 1,861,641 Nicholson et al June 7, 1932 2,103,378 Oestnaes et al Dec. 28, 1937 2,230,770 Van Almelo Feb. 4, 1941 2,335,888 Stilwell, Jr Dec. 7, 1943 2,355,951 Cofieen et al Aug. 15, 1944 2,368,193 Boynton Jan. 30, 1945 2 391,238 Horman Dec. 18, 1945 2,415,448 Stilwell, Jr Feb. 11, 1947 

